I think you (RSRH) need to delve a bit more deeply into the writings of your leader and his prominent followers. Zionismus would be an easy place to start researching Hirsch’s feelings on the subject. Also, one of the 19 letters is on the subject. Certainly at no point did he or his followers declare austritt against the Zionists; the battle against the Zionists was entirely different from the battle against Reform.
The Zionist movement was (and is) ideologically indifferent to religion, as opposed to the Reform movement which is a religious movement. The animosity of Zionists against the Jewish religion stems from the disagreement that religion has anything to do with being a Jew. To Zionists, a Jew is only from a nationalistic or racial point of view. Consequentially, the religious Jews who oppose this belief are in turn scorned for undermining the Zionists.
As many have called them, the German Orthodox Jews are zionists against Zionism. There were even religious kibbutzim from Germany.
Exercise restraint in applying the austritt philosophy.